Temperature-Dependent Tunneling in Furan Oligomer Single-Molecule Junctions
Temperature-Dependent Tunneling in Furan Oligomer Single-Molecule Junctions
复制标题
呋喃低聚物单分子连接中的温度依赖性隧道效应
DOI：
10.1021/acssensors.0c02278
复制
发表时间：
2021
期刊：
影响因子：
8.9
通讯作者：
Hihath Joshua
中科院分区：
文献类型：
--
作者：
Li Haipeng B.;Xi Yan-Feng;Hong Ze-Wen;Yu Jingxian;Li Xiao-Xia;Liu Wen-Xia;Domulevicz Lucas;Jin Shan;Zhou Xiao-Shun;Hihath Joshua
单分子结中常见的两种电荷输运机制是相干隧穿和非相干跳跃。人们普遍认为，隧道过程产生与温度无关的电导行为，而跳跃过程表现出随温度升高而增加的电导。然而，最近有人提出，由于接触的费米能量的热展宽，隧穿也可以产生依赖于温度的输运。在这项工作中，我们研究了一系列刚性的平面呋喃低聚物，它们没有旋转的内部自由度，以考察直接在较宽的温度范围(78-300K)内隧道输运的温度依赖性。我们的结果表明，电导从与温度无关的区域转变为与温度相关的区域。通过考察各种跳跃和隧穿模型，以及电导的温度依赖关系和分子轨道能量偏离费米能级的关系，我们得出结论：热辅助隧穿是这些体系中电导随温度变化的主要原因。
Two commonly observed charge transport mechanisms in single-molecule junctions are coherent tunneling and incoherent hopping. It has been generally believed that tunneling processes yield temperature-independent conductance behavior and hopping processes exhibit increasing conductance with increasing temperature. However, it has recently been proposed that tunneling can also yield temperature-dependent transport due to the thermal broadening of the Fermi energy of the contacts. In this work, we examine a series of rigid, planar furan oligomers that are free from a rotational internal degree of freedom to examine the temperature dependence of tunneling transport directly over a wide temperature range (78–300 K). Our results demonstrate conductance transition from a temperature-independent regime to a temperature-dependent regime. By examining various hopping and tunneling models and the correlation between the temperature dependence of conductance and molecular orbital energy offset from the Fermi level, we conclude thermally assisted tunneling is the dominant cause for the onset of temperature-dependent conductance in these systems.